Skin samples from patients with systemic sclerosis (SSc) are not widely available to investigators studying pathogenesis. To derive the greatest value from these samples it is important that they are associated with clinical data, in particular the modified Rodnan skin score (MRSS), but also ideally other organ involvement The Boston University Medical Center Scleroderma Program under the leadership of Dr. Lafyatis and through NIH U01 funding has collected and is continuing to collect such well-characterized biopsies. In addition in many cases in patients with early diffuse SSc biopsies are being collected every 6 months, so that the evolution of the disease and the relationship to changes in protein staining in the skin tissues can be compared. Dr. Bhawan, Dermatopathologist and Director of the BUMC Dermatopathology Laboratory, will direct the Skin Pathology Core (Core B). The Core will process these and other biopsies provided by Core Center Investigators into 8-sample tissue blocks containing either 6 different SSc and 2 healthy control biopsies ("Discovery slides"), 6 temporally evolving skin changes in individual patients and 2 healthy control biopsies ("Disease Progression slides"), or 2 SSc and 6 other diseases including wound tissue, psoriasis, keloid and nephrogenic systemic fibrosis (Specificity slides). Murine skin will be collected from murine models of SSc: cGVHD, bleomycin, Tsk and other SSc models, as well as control mice for similar multi-tissue slide preparations. The Core will assist Investigators or stain these slides in the Core as the Investigator requests with proteins under study for new pathological processes implicated in the vasculopathy, fibrotic or immune response in SSc and murine SSc model skin. Core B will also evaluate histochemical or immunohistochemical staining intensity using quantitative (image analysis) or semi-quantitative methods. Sample staining will be correlated with MRSS and other clinical parameters, and past staining patterns in slides from the same block can also be compared. These slides will provide an unparalleled resource for discovery of pathogenic mechanisms in skin pathogenesis of SSc.